Background: Acute kidney injury (AKI) is the main life-threatening complication of crush syndrome (CS), and myoglobin is accepted as the main pathogenic factor. The pattern recognition receptor retinoicacid-inducible gene I (RIG-I) has been reported to exert anti-viral effects function in the innate immune response. However, it is not clear whether RIG-I plays a role in CS-AKI. The present research was carried out to explore the role of RIG-I in CS-AKI. Methods: Sprague-Dawley rats were randomly divided into two groups: the sham and CS groups (n=12). After administration of anesthesia, the double hind limbs of rats in the CS group were put under a pressure of 3 kg for 16 h to mimic crush conditions. The rats in both groups were denied access to food and water. Rats were sacrificed at 12 h or 36 h after pressure was relieved. The successful establishment of the CS-AKI model was confirmed by serum biochemical analysis and renal histological examination. In addition, RNA sequencing was performed on rat kidney tissue to identify molecular pathways involved in CS-AKI. Furthermore, NRK-52E cells were treated with 200 μmol/L ferrous myoglobin to mimic CS-AKI at the cellular level. The cells and cell supernatant samples were collected at 6 h or 24 h. Small interfering RNAs (siRNA) was used to knock down RIG-I expression. The relative expression levels of molecules involved in the RIG-I pathway in rat kidney or cells samples were measured by quantitative real-time PCR (qPCR), Western blotting analysis, and immunohistochemistry (IHC) staining. Tumor necrosis factor-α (TNF-α) was detected by ELISA. Co-immunoprecipitation (Co-IP) assays were used to detect the interaction between RIG-I and myoglobin. Results: RNA sequencing of CS-AKI rat kidney tissue revealed that the different expression of RIG-I signaling pathway. qPCR, Western blotting, and IHC assays showed that RIG-I, nuclear factor kappa-B (NF-κB) P65, p-P65, and the apoptotic marker caspase-3 and cleaved caspase-3 were up-regulated in the CS group (P<0.05). However, the levels of interferon regulatory factor 3 (IRF3), p-IRF3 and the antiviral factor interferon-beta (IFN-β) showed no significant changes between the sham and CS groups. Co-IP assays showed the interaction between RIG-I and myoglobin in the kidneys of the CS group. Depletion of RIG-I could alleviate the myoglobin induced expression of apoptosis-associated molecules via the NF-κB/caspase-3 axis. Conclusions: RIG-I is a novel damage-associated molecular patterns (DAMPs) sensor for myoglobin and participates in the NF-κB/caspase-3 signaling pathway in CS-AKI. In the development of CS-AKI, specific intervention in the RIG-I pathway might be a potential therapeutic strategy for CS-AKI.

Peng-Tao Wang;Ning Li;Xin-Yue Wang;Jia-Le Chen;Chen-Hao Geng;Zi-Quan Liu;Hao-Jun Fan;Qi Lv;Shi-Ke Hou;Yan-Hua Gong

General Hospital of Tianjin Medical University,Tianjin 300052,China;Institute of Disaster Medicine,Tianjin University,Tianjin 300072,China;State Key Laboratory of Medicinal Chemical Biology,Nankai University,Tianjin 300350,China;Tianjin Key Laboratory of Disaster Medicine Technology,Tianjin 300072,China;Wenzhou Safety(Emergency)Institute,Tianjin University,Wenzhou 325000,Zhejiang China

军事医学研究（英文）

[1]Peng-Tao Wang;Ning Li;Xin-Yue Wang;Jia-Le Chen;Chen-Hao Geng;Zi-Quan Liu;Hao-Jun Fan;Qi Lv;Shi-Ke Hou;Yan-Hua Gong-.RIG-I, a novel DAMPs sensor for myoglobin, activates NF-κB/caspase-3 signaling in CS-AKI model)[J].军事医学研究（英文）,2022(01):40-52

retinoicacid

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